General Information

Generator

This generator (Figure 3) is a high quality portable (requires a trailer for transport) power source for telecom sites, lighting facilities, power tools, submersible pumps and other industrial and construction machinery.

Engine Operating Panel

The “Engine Operating Panel” is provided with the following: Tachometer

Water Temperature Gauge Warning Lamp

Fuel Leak Detected Alarm Lamp Pre-Heat Lamp

Oil Pressure Gauge

Charging Ammeter Gauge Fuel Level Gauge

Panel Light/Panel Light Switch ECU Controller

Engine Speed Switch

Generator Control Panel

The “Generator Control Panel” is provided with the following: Frequency Meter (Hz)

AC Ammeter (Amps)

AC Voltmeter (Volts)

Ammeter Change-Over Switch

Voltmeter Change-Over Switch Voltage Regulator

3-Pole, 175 amp Main Circuit Breaker

“Control Box” (located behind the Gen. Control Panel)

•Automatic Voltage Regulator

•Current Transformer

•Over-Current Relay

•Starter Relay

•Voltage Selector Switch

Open Delta Excitation System

This generator is equipped with the state of the art “Open- Delta” excitation system. The open delta system consist of an electrically independent winding wound among stationary windings of the AC output section.

There are four connections of the open delta A, B, C and D. During steady state loads, the power from the voltage regulator is supplied from the parallel connections of A to B, A to D, and C to D. These three phases of the voltage input to the voltage regulator are then rectified and are the excitation current for the exciter section.

When a heavy load, such as a motor starting or a short circuit occurs, the automatic voltage regulator (AVR) switches the configuration of the open delta to the series connection of B to C. This has the effect of adding the voltages of each phase to provide higher excitation to the exciter section and thus better voltage response during the application of heavy loads.

The connections of the AVR to the AC output windings are for sensing only. No power is required from these windings.

The open-delta design provides virtually unlimited excitation current, offering maximum motor starting capabilities. The excitation does not have a “fixed ceiling” and responds according the demands of the required load.

Engine

This generator unit incorporates an ISUZU BJ-4JJ1X diesel engine.This engine is designed to meet every performance requirement for the generator. Reference Table 2 for engine specifications.

In keeping with MQ Power’s policy of constantly improving its products, the specifications quoted herein are subject to change without prior notice.

Electric Governor System

The electric governor system controls the RPMs of the engine. When the engine demand increases or decreases, the governor system regulates the frequency variation to ±.25%.

Output Terminal Panel

The “Output Terminal Panel” is provided with the following: Three 120/240V output receptacles (CS-6369), 50A Three auxiliary circuit breakers, 50A

Two 120V output receptacles (GFCI), 20A Two GFCI circuit breakers, 20A

Five output terminal lugs (3Ø power)

Extension Cables

When electric power is to be provided to various tools or loads at some distance from the generator, extension cords are normally used. Cables should be sized to allow for distance in length and amperage so that the voltage drop between the generator and point of use (load) is held to a minimum. Use the cable selection chart (Table 6) as a guide for selecting proper extension cable size.

page 16 — DCA70USI3can 60 hz Generator • operation and parts manual — rev. #1 (09/24/13)